When operating a dimmer or other pulse-width-dependent circuit, replicating the pulse width can become important. If a pulse width at an input varies significantly from the corresponding output pulse width, this can cause significant problems. For example, a pulse may not achieve an output signal, as slew rate limits may stop the output stage from turning on. Likewise, an intended effect of a certain pulse width may be limited or missed completely, due to changes in pulse width to provide an output.
Many applications use a pulsed power waveform to provide power to a component. For example, light emitting diodes (LEDs) can be driven with a pulsed waveform. Likewise, sound equipment such as sub-woofers may be driven with a pulsed waveform to provide power. Moreover, dimmer switches are often implemented with a pulse waveform as a power output to the component to be dimmed or controlled.
Thus, it may be useful to find a way to make the pulse-width of the output of a circuit close to identical to the input. In particular, it may be useful to measure an input pulse width, to allow for calculation of a delay to a pulse width output (e.g. a rising edge of an output pulse) or to measure a delay to the end of the input pulse (e.g. a falling edge of the input pulse). In such an instance, dynamic range may be improved, and a situation where the output never turns on may be avoided.